1. Field of the Invention
The present invention relates to a drug delivery device having an end-piece surrounded by a collar and specific coupling means for coupling said end-piece to a connector.
2. Description of Related Art
Drug delivery devices usually comprise a hollow body forming a reservoir for containing a medical product. In addition, the distal end of the body forming the reservoir usually comprises an end-piece in which an axial passageway is arranged through which the said product is ejected from the reservoir.
In this application, the distal end of a component or of a device must be understood as meaning the end furthest from the hand of the user and the proximal end must be understood as meaning the end closest to the hand of the user.
Moreover, the reservoir and end-piece of a drug delivery device may be made of various materials such as glass or plastic. When it is known that the stability of the product stored in the reservoir is not impacted by the plastic nature of the wall of the reservoir, it is desirable to have a drug delivery device made of plastic materials, so as to avoid the common risks associated with the handling of glass material. Actually, when drug delivery devices made of glass material happen to break, not only the product they may contain is lost, but the resulting bits of glass material constitute danger for the persons who happen to be around. Moreover, the product lost may also generate a danger when such product is for example a toxic drug.
It is also desirable to have drug delivery devices made of plastic materials when these drug delivery devices are prefilled with the product and provided to the final user in a prefilled state: risks of breaking the drug delivery device during the various operation it is submitted to before use, such as the steps of prefilling, sterilization, packaging, transport, storage, are therefore substantially limited.
The handling of products, such as liquid medicine, in particular for a parenteral administration to a patient which is carried out via a perfusion device, as often in hospitals or in emergency situations, implies, in a general manner, the use of connectors, such as IV (Intra Veinous) connectors which link the drug delivery device, containing the product to be delivered, to the vein of the patient, usually via an IV line. Of course, the drug delivery device, in particular its end-piece and the connector must be assembled together correctly and securely.
In this view, the drug delivery device usually comprises an external collar surrounding the end-piece, this collar being intended to be connected to a connector so as to facilitate the transfer of the product from the end-piece of the drug delivery device to the connector, and then in the IV line.
At the time the connector is connected to the collar, the collar is submitted to a stress resulting from the force applied in order to connect the connector thereon. The intensity of the force applied may vary depending on the way the connector is connected on the collar: for example, the connector may be connected to the collar by force fitting of by screwing. The intensity of the force applied also depends on the user. As a consequence, the stress to which the collar is submitted to when the connector is connected thereon is not controllable.
Moreover, problems have been reported concerning the assembling of IV connectors to some types of drug delivery devices, in particular for drug delivery devices having their collar as described above made of plastic material such as cycloolefin polymers and/or copolymers. In particular, it happens that the collar surrounding the end-piece of the drug delivery device breaks at the time it is submitted to the necessary stress for connecting the connector thereon, for example by screwing. In such a case, the connector is not securely and correctly connected to the end-piece of the drug delivery device, and the administration of the medicine is made impossible or, at best, delayed. Moreover, such a phenomenon may also cause a risk of syphoning effect, ie uncontrolled delivery of drug due to difference of height between the drug delivery device and the catheter, which are both linked with the IV line.